


Upgrades

by Kawaii_chubby_cheeks



Category: Undertale (Video Game)
Genre: Anal Fingering, Anal Sex, Angst with a Happy Ending, Ecto-Genitalia (Undertale), Ecto-Tongue (Undertale), Established Relationship, First Time, Fluffy Ending, Hand Job, Intersex Character, M/M, Masturbation, Oral Sex, Porn With Plot, Post-Undertale Pacifist Route, Robot Sex, Switching, Vaginal Sex, papyton, slight angst
Language: English
Status: Completed
Published: 2017-01-14
Updated: 2017-01-14
Packaged: 2018-09-12 09:28:09
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 7,622
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9065857
Author URL: https://archiveofourown.org/users/Kawaii_chubby_cheeks/pseuds/Kawaii_chubby_cheeks
Summary: Papyrus and Mettaton want to be more intimate and find out how passionate they feel about it.





	

**Author's Note:**

> All characters belong to Toby Fox, of course! I only own the idea of this fanfiction and what I write.
> 
> P.S:  
> This is my first time writing about ecto-biology, so forgive me for being awkward at any time during this fic!

It was two months into the relationship that there was something the two unspokenly knew they were missing out on. It wasn't as if it was something they didn't want, it's just that the couple literally had no idea of how to go about it when the chance came forth. The subject of intimacy was complicated enough to start with between a clumsy skeleton and a killer robot. Papyrus lacked lips and experience, which he made up with being loyal and quite good at cloth cleaning metals made from armors. Plus his cooking skills weren't terrible with his cooking classes continuing, and date night was always a blast. Mettaton lacked the need for privacy and modesty, which lead to bragging too much on his sugar skull and flirting with his boyfriend in the most close up and touchy ways- In front of the skeleton's protective brother. It ended in a few ass kickings with terrifying blue abilities, but Mettaton didn't care. He made up for his narcissistic tendencies with amazing gifts and his full attention on his lover whenever they had time alone. They would press teeth and rubber lips together sometimes in loving kisses and Papyrus would sometimes dare to put his hand on the star's lower back for a few seconds. But the two really had no idea how to go about starting to have sex.

"Papyrus, is your brother home?" Mettaton asked. He smiled at his boyfriend, his voice a soft purr. The two were in the new apartment in a building that the tall skeleton moved into with his older brother. Sans didn't seem to trust the two alone and usually made it a point to stick around. But today Mettaton has scarcely seen the shorty. It had him a little on edge. 

"NO, HE IS ATTENDING A PTA MEETING WITH MS.TORIEL TODAY." Papyrus told him. He sat down on the sofa, comfortably putting his spine to the cushion behind him and putting one long leg over the other. "DO NOT MIND HIM, ANYWAY. SANS MEANS WELL." 

"I guess you're right, darling." Mettaton said. He eased down onto the sofa beside his boyfriend. There was some space between them and it was obvious they wanted to close it, sort of unsure how they wanted to. A soft whir emitted from the robot as his gaze traveled to the other. He could see him gulping by the twitch in his jaw. 

"I THINK A RERUN OF ONE OF YOUR SHOWS IS ON METTATON, DEAR." Papyrus said. It was awkward whenever he used a pet name. His character was too innocent for it.

It would have been nice to sit there and bask in the knowledge that he was a widely known star now up on the surface, but after two months of having this ongoing relationship, Mettaton could hear the slight whine in Papyrus' voice that hinted at his need for affection- Affection that the killer robot happily gave forth with maximum effort. 

"Oh, sugar skull!" Mettaton made a point of dramatically extending one leg into the air while he sat back on the arm of the couch and pointed his other leg out onto his boyfriend's lap. "Don't be silly. Paying attention to you is far more important than watching one of my television programs!" 

It made the robot's soul thump happily in its container to watch as Papyrus' magic made his cheeks go orange. Always a perfect sight on its own, Mettaton saw it as his personal little heaven to see the simple but cute flushed expression. He would gladly keep him blushing if it meant seeing him in such a beautiful manner. He put his legs down so that his feet hit the cheap carpet floor. It was difficult for him to understand why the brothers would not accept his money and get a better home. But he guessed it had to do with the shorter's pride. Nevertheless, Mettaton scooted close so his hip touched Papyrus'. The sight of his cute blush only increased with their closeness. He leaned in and pressed his lips gently to the skeleton's teeth, enjoying the click that sounded from the contact. He could hear the other suck in a sharp but unnecessary breath. Mettaton giggled. Oh, he had himself quite the cutie.

"METTA. ." Papyrus began. 

He was shut up by the feeling of a curious though sudden hand running up his shirt and metal fingers wrapping around his ribs one by one, caressing them. Papyrus bit back a moan and arched slightly into the delightful touch. Every stroke against his bone sent fluttering pleasure to his soul. It was a warm and tingling sensation that left him shuddering. Papyrus felt as if he were becoming light headed from the stimulation. His soul thumped wildly as heat pooled in his soul the more his teeth were kissed at and his ribs eagerly caressed. The heat traveled down to his pelvic bone. The wonderful heat radiated in his lower bones and the attention to his body ended as Mettaton pulled back with a gasp. 

Papyrus slowly looked down in confusion to see why his ribs were no longer being teased. His soul had formed an erection, twitching and glowing obvious orange through his shorts. No wonder Mettaton had stopped. He was sporting a full on boner just from simply having his bones massaged! Papyrus could feel his cheekbones flaring with blush in embarrassment. 

"OH MY GOD. I'M SO SORRY. I DON'T USUALLY JUST GET A STIFFY WHEN MY BONES ARE TOUCHED. I SWEAR-" Papyrus went into a panic. His boyfriend could only stare wide eyed, clueless on what to do about the stiff dick in his love's shorts. "Y, YOU JUST SEEM TO GET ME ON A SENSITIVE DAY, ERM. .!" 

Mettaton took a moment to force himself to look away. Why did he have to know so little about this topic? It was so embarrassing! "Well, sugar skull. . . We've been dating for two months and the most we've done is kiss. . . So I guess it's ok for your body to be excited at the idea of. . . You-know-what, darling."

Papyrus now tried vainly to conceal his arousal. But the heat surrounding his pelvis would not cease even if he lifted his legs onto the couch and hugged his knees into himself to try and hide the glow in his trousers. "YOU THINK SO? BECAUSE I WOULD RATHER NOT MAKE YOU UNCOMFORTABLE."

"Sugar skull! You could never make me uncomfortable. Not even with an unexpected. . . Guest." Mettaton could feel the rubber on his cheeks heating up. It was not common for something like this to happen and in honesty, the famous robot barely knew about the process of sex, since he has never had genitals to use. "But, uh. . . Do you think it should be handed- If it needs to. I have no idea, dear." 

"METTA!" Papyrus squeaked bashfully. It was nearly impossible to ignore the heat still radiating from his soul. But he didn't know if they were at the level to be this intimate yet. He looked away with a bit of shame. "UM. . . I CAN HANDLE IT. IT WILL JUST TAKE A WHILE." 

This raised the others curiosity. Maybe this was his chance to learn about sex first hand! But one sided. And without it being actual sex. Mettaton beamed slightly. "What do you mean? Show me how you plan to 'handle it'."

"UM. . ALRIGHT, BUT DO NOT EXPECT IT TO BE A BIG SHOW!" Papyrus fidgeted his shorts off after lowering his legs back down. It took a moment to get them down to his ankles so that when he was finished he could pull the article of clothing right back on. His erection stood to attention, bright orange and thick and long. It looked heavy from the looks of it.

Visibly big eyed, Mettaton stared now. The point of this moment was to get a look at how a boner was handled, so might as well be shameless. Plus this was his boyfriend! What did he have to be ashamed of? He flashed an assuring smile his love's direction, hoping to encourage him. Papyrus gulped a nonexistent lump in his nonexistent throat as he wrapped his phalanges around the base of his cock, sucking in sharply. It had been a long time since he'd last done such a thing as this. His boner twitched as he began to slowly stroke from the base to the tip, barely gripping himself. Papyrus groaned quiet as to try and not seem too worked up but having his boyfriend watch him stroke himself was honestly causing more heat than he would have desired to his groin. He heard a soft whir noise but tried to ignore it and closed his eyes. His wrist twisted to a faster stroking motion, his fingers ever so lightly putting pressure on his cock now, giving the tip a few gentle squeezes that made his soul thump against his ribcage. 

"Is it supposed to drip. . ?" 

The voice snapped him out of his pleasured trance. Papyrus looked at his celebrity boyfriend's beautiful, curious expression the to his shaft. Precum collected at the tip, ready to spill. He nodded. "Y, YES. . . I AM CLOSE TO FINISHING." It was hard to explain coming so he wasn't really going to bother. 

"Do you want help?" Mettaton asked as if it were normal. He was eyeing him in fascination. "P. . Please."

Thinking of the other's hand on his cock made it twitch with slight anticipation. Papyrus leaned his back on the couch and shifted to spread his legs a bit to give a better view of his glowing genitals. Mettaton had yet to pull his gaze away from the large organ in front of him, looking hypnotized by it. His pale cheeks were flushed the same passionate pink as the soul cased in his middrift.

Mettaton wrapped his fingers delicately around his shaft and began to give unsure strokes. The metal on his fingers felt cool compared to the heat they were wrapped around. Papyrus swallowed back a groan as Mettaton tried to apply soft pressure around his dick while his wrist moved into a faster motion. It wasn't bad for a first time, but he knew to expect good things from his naturally talented lover.

"YOU'RE NOT GOING TO BREAK IT IF YOU GRIP IT." Papyrus mumbled. His face was rather flushed by now. He hissed through his teeth at feeling Mettaton grow a little confident in his touching. He stroked faster still and gave the tip a soft squeeze every time he reached it. Heat grew more and more, driving the lust filled skeleton to the edge gradually. He clenched his eyes shut to hide the rolling back while Mettaton eagerly pumped his shaft. Papyrus could feel the other's hand getting warmer from his stroking. 

It was becoming so difficult to not finish. But he guessed it was the whole point of them giving his cock attention. Papyrus huffed under his breath, trying to wrap his head around the wonderful sensations hitting his soul from his groin. The heat was starting to become too much. The skeleton gripped the sofa cushion his ass was planted on and grit his teeth as he felt a tingle start to overwhelm his senses. 

"METTATON. . !"

The robot looked up at the other to see his expression of bliss before he gasped, semen spurting onto his face. Mettaton let out a small squeak, unsure how to react. His hand stopped moving and retracted to feel the sticky substance that now decorated his cheeks, chin, and lips. It was the price to pay for sitting so close to the splash zone. 

"Papy, dear, what even is this-?" Mettaton began with utter confusion. He didn't notice the door was opened to the apartment until he heard a soft thud on the carpet. Looking up, he saw a short and very angry skeleton in his signature hooded blue jacket. Beside him was a dropped to-go bag from Grillby's. The robot felt as if something were crawling on his back. And looking at the other, it seemed as if Papyrus did as well. 

"What the Hell are you doing to my brother, you hussy?" Sans growled. He picked up his to-go bag and shut the door behind him, slamming it. The sound echoed awkwardly as no one dared to answer Sans.

It took a moment before Papyrus found his bearings and pulled his shorts back up. His soul had lost it's lust and instead thumped with fear. He stood to his feet and tried to stand in front of Mettaton protectively, knowing he didn't fully understand the situation. "SANS, PLEASE LET ME EXPLAIN BEFORE YOU MAKE ANY RASH DECISIONS."

"He has your cum on his face, bro!" Sans exclaimed. "What is there to explain? He's a little slut, I fucking called it!" 

"WH, WHAT?" Papyrus frowned. He looked behind himself to see Mettaton struggling to wipe his face clean on the sofa seat. The robot was visibly upset and trying to hide it as he gave up his attempt at cleaning up and instead rested his cheek on the cushion. Papyrus wanted to very badly comfort him and assure him he did nothing wrong, but he had to deal with his sibling first. 

Papyrus looked at Sans. "DON'T CALL METTA SUCH A THING, BROTHER. HE WAS ONLY TRYING TO HELP AFTER I GOT WORKED UP." 

"I'll call him what I damn please. Now step aside so I can take the trash out." Sans looked behind his sibling, making it obvious he didn't actually mean what was in the garbage bin. 

Papyrus ignored the way his soul felt as if it may thump right through his ribcage. Anger began to pool within the boney monster. "SHUT YOUR FILTHY MOUTH, SANS!" He snapped. Papyrus didn't know what was coming over him but he couldn't stop it. "METTATON HAS DONE NO WRONG ALL THROUGH OUR RELATIONSHIP. HE HAS MADE NO ATTEMPTS TO SEDUCE ME. I STARTED TO GET EXCITED WHEN HE TOUCHED MY RIBCAGE AND IT CONTINUED FROM THERE BECAUSE I LET IT. BUT, NONETHELESS. METTATON DOESN'T EVEN HAVE GENITALS, BUT I WILL LET HIM INTO.MY BED IF I SO PLEASED BECAUSE IT IS MY CHOICE. "

Sans stared at him, unsure how to approach the situation now. He had never heard his sweet little brother speak to him this way. But then again they've never had issues like this before. Sans puffed out his chest. "Papyrus, listen to me-" 

"NO, YOU LISTEN TO ME."

Sans tensed. He looked up at the taller skeleton seriously. Maybe it was time to stop babying him. . . But knowing his brother was doing these things now. . . How is Sans supposed to suddenly get used to it? Especially when Papyrus is with a celebrity known for his sexual attraction. Sans sighed deeply. "Ok. Ok. I won't get into your business. But if he hurts you-" 

"I KNOW HE WON'T, BROTHER." Papyrus said simply. He turned his back to the shorter and knelt down to wrap his arms around Mettaton, whom clung to him with a small noise of worry.

The couple moved from the living room to the bathroom. Papyrus wet a wash cloth before he gently wiped his lover's face clean, earning himself a soft, worried whir noise. "SHHH. IT IS OK, I'VE GOT YOU, METTA." 

"Papy. . ." Mettaton spoke up for the first time in the time after Sans catching them. "Am I really a slut for what I did with you?" 

The tall skeleton looked at him as if he'd gone insane then in one motion brought him into his arms. "YOU ARE NOTHING OF THE KIND! METTATON, LOVE YOU ARE VERY DEVOTED AND I COULD NOT IMAGINE YOU BEING THE TYPE TO SLEEP AROUND.EVEN IF YOU ARE A SENSUAL AND AFFECTION PERSON. SANS HAD NO RIGHT TO SAY WHAT HE DID." 

Biting his bottom lip hard to keep it still, Mettaton pressed his forehead on the other's shirt and tried to not get worked up. Hearing such sweet things helped him to feel better but now the celebrity couldn't think of how he could possibly be lucky enough to be with a person that saw him so positively. "Oh, sugar skull," Mettaton gazed up at him. His eyes were filling with tears made up of oil. "I love you so much." 

Papyrus blushed deep orange. It was rare for them to say that to each other and when they did, especially the robot currently crying into his shirt, it was rather special. People may think with how affectionate they were publicly that it may be said every minute but on the contrary they didn't want the phrase to get old fast. Papyrus pressed his teeth to his boyfriend's forehead and felt him relax into his arms. He heard a soft beep begin and knew it would be best if they moved.

"I KNOW YOU DO, METTA." Papyrus walked with him out of the bathroom and to his bedroom, easing him to sit by the power outlet by his new bed- Which disappointingly was not a racecar. Mettaton smiled gratefully as his cord was taken from his upper back and plugged in so he could charge. The beep stopped once he began charging. 

"See you after my beauty rest, darling." Mettaton smiled at him. His eyes closed as he went into sleep mode. 

Smiling at how peaceful the other looked, Papyrus let himself stare for a moment. Then he willed himself to look away so he could make a phone call. Papyrus skimmed through his phone contacts only to feel a little defeated. How did he not have her number? Well, he could ask her girlfriend, since he proudly considered them close friends. He punched in the phone number he knew by heart now then held his phone to his skull, listening to the impatient ringing sound. It was answered on the second ring. Papyrus felt a little burst of happiness to know she wasn't busy. He left his bedroom so that he was alone for his conversation. 

"Hey, dork." Undyne greeted him warmly from her end of the receiver. "What's up?" 

"HELLO, UNDYNE! METTATON IS SPENDING HIS DAY OFF WITH ME. RIGHT NOW HE IS CHARGING UP. MAY I ASK IF I CAN PERHAPS GET ALPHYS' TELEPHONE NUMBER?" Papyrus felt awkward asking but he had questions that only the creator of the robot's body could answer. "I HAVE SOMETHING IMPORTANT TO ASK." 

"I'm sure she can tell you herself." Undyne responded as if this were no big deal. "Baaabe. Here's the phone. It's the Skele-dork." 

There was a small shuffling sound before Alphys spoke into the phone. "H, hello? Pa-Papyrus?" 

"GREETINGS, MS.ALPYS! THIS IS GOING TO SOUND OFDD, BUT I HAVE SOME QUESTIONS ABOUT METTATON'S BODY AND THE FEATURES." Papyrus said. 

Alphys could not help sounding a little interested. "I'm g, glad to explain th, things! What do y, you need to kno, know?" 

Papyrus didn't know how to make this topic into a casual conversation. It was something more meant for your closest friends but he that Alphys would be the only person with answers. He ignored the nervous thump of his soul and took a deep breath. "IS IT POSSIBLE TO HAVE PHYSICAL RELATIONS WITH A ROBOT? I KNOW THAT I HAVE YET TO SEE SUCH PARTS, BUT I WAS WONDERING. .. ." 

His question was followed by a moment of awkward silence before she spoke once more. "I, I have not upgraded his body with sexual organs of any kind y, yet. Seeing as th, though he had not had a relationship where h, he has wanted to get as intimate y, yet. But if h, he asked, I will gladly t, try to give him wha,whatever parts he would prefer. His body will easily read a chip that gives him physical descriptions and f, functions ."

Feeling his nerves get a bit worse, Papyrus didn't know if he could ask the scientist's opinion on if she might think Mettaton is ready for that type of intimacy with him. Not after the mess that just happened. It wasn't as if Papyrus was not happy with their current relationship the time being but he kind of wanted to take things to the next level if Mettaton was sure he wanted it. Papyrus looked over his shoulder to his bedroom door and hoped that nothing could be heard when Mettaton is in sleep mode. He thanked Alphys before he received her phone number for any questions he had later on, then he hung up politely after telling Alphys he hoped she and Undyne had a nice evening.

Sighing, Papyrus turned his phone off and considered going back to his bedroom to read comic books on super heroes or going to see if Sans was willing to forgive him for the bad terms they left on earlier. Reading a few pages of Spiderman was much more pleasant, though Papyrus knew he had to reconcile with his brother.

"BROTHER? ARE YOU IN THERE?" Papyrus approached the older's bedroom door and knocked against it.

After a moment the door opened. Sans looked up at him with a sad look. This was nothing like his usual joking smile which had Papyrus feeling a slight panic. Sans put up the hood of his jacket defensively. "What's up, bro?" 

"I AM SORRY FOR SNAPPING AT YOU. LOSING MY TEMPER WAS AND IS NOT THE ANSWER TO HANDLING A SITUATION." 

"Papyrus. . ." Sans looked wide eyed at him. Then he looked away, an embarrassed expression taking up his face. "Fuck. I'm supposed to be the mature brother, aren't I? Heh." He nodded once in the direction of the living room. "Let's go talk for a moment. A real talk. Brother-to-brother."

"O, OK." Papyrus felt his nerves start up again. He entered the living room with his brother and sat down on one side of the couch. Sans sat at the other. Silence hit them for a moment. It was the that Papyrus realized he didn't know what this chat would be about. All he knew was he wanted to keep his wonderful relationship with his brother. 

"Papy," Sans began finally after the longest moment in Papyrus' life. "You're nineteen and I need to stop treating you as a child. It's not helping you as the young adult you are." 

Papyrus didn't speak up. 

Sans continued. "I can't make choices for your life now. You can pursue any dream you want and even be with who you want in whatever way you want. So. . . Uh. . . How do I put this. . ?" The short skeleton made awkward hand gestures. "Be a robot fucker if you wanna, I guess? It's wrong of me to get in your love life?? Be safe???"

Papyrus didn't say anything now, but only because he was at a loss for words. How was he to respond. The brothers shifted awkwardly on the couch on their respectable ends. It was nearly impossible to look each other in the eye at the moment.

"IS THIS ALL THAT NEEDED TO BE SAID, BROTHER?" Papyrus asked after another silent moment. Sans nodded quickly.

"Awkward sibling hug?" Sans asked.

Papyrus managed a smile. "AWKWARD SIBLING HUG." He leaned in and both skeletons pat each other on the back before going their separate ways. Papyrus to his bedroom and Sans out of the apartment to go back to Grillby's./p>

*    *    *

Twenty minutes into lying on his front with a comic open under his face, Papyrus heard a soft beep and brought his gaze to his resting boyfriend. He knew it was time to wake him up by now. Closing his comic book and putting it to the side, Papyrus moved off of his bed to unplug the power cord from its outlet. The skeleton sat down in front of his love and watched his eyes open. Mettaton blinked a couple of times only to smile big at Papyrus.

"Good evening, sugar skull! How long was I out?" Mettaton tilted his head.

"YOUR NAP WAS RELATIVELY SHORT. ABOUT AN HOUR. ." Papyrus smiled at him. He shifted himself to sit beside the other and wrapped his arm around his waist. Mettaton comfortably put his cheek on his shoulder, whirring softly in content.

". . . You spoke to Sans?"

". . . Y, YES. NOT TOO LONG AGO WE HAD A SMALL CONVERSATION. WE BOTH HAVE AN UNDERSTANDING THAT YOU ARE MY BOYFRIEND AND WHAT WE DO IS UP TO US."

Mettaton lifted his head up to look at him better. "Really, my lovely skeley? D, does that mean I can stay the night now and h, hug up to you more openly here?"

Seeing his boyfriend so happy about this made Papyrus' soul thump in his being. Why did he have to have such a cute partner? Smiling happily, he nodded and it was less than a second later that Mettaton tackled him, nearly dislocating several bone joints. But in honesty Papyrus didn't care. It was a warm hug from his loving boyfriend and he wouldn't mind his arm or something falling off in the process. Luckily nothing fell off and he was only pressed against the wall by his bed. Mettaton looked at him happily, black lips pointed into a big grin. In that moment Papyrus realized how perfect the moment felt for a kiss. Being between a wall and his beloved wasn't bad at all. It actually made his soul heat up. Especially with their faces so close. Mettaton gulped nervously, his face starting to go the same colour as his soul.

"Papyrus. . ." Mettaton's voice came out as a whisper. "Is it ok if I touch your ribs again?" 

For some reason having the other ask sounded so sexy. Papyrus shivered, nodding his head. "YOU HAVE FULL PERMISSION TO TOUCH AS YOU PLEASE."/p>

Mettaton smiled. He pressed a kiss to the other's cheek then he slowly pushed his hand up into his shirt. His fingers delicately danced over one rib followed by the next, barely touching but doing enough to have Papyrus panting and trying to hold noises in. "You're so cute, sugar skull. . . Don't feel like you have to keep in your voice." 

"H, HOT. . !" Papyrus gasped. His soul felt like it was going to melt from all the teasing to his ribs. He panted softly when Mettaton rubbed harder into the sensitive bone. Papyrus started to feel dizzy and a wonderful heat pooled at his groin. "METTA. . . IF YOU KEEP THIS UP, I'M GOING TO GET-" 

"Hard? I know, lovey." Mettaton purred. He reached down with one hand and slid his fingers into the other's shorts, feeling his pelvis. He watched how his boyfriend squirmed underneath him with pleasure only before he felt his heated erection form. Mettaton tried to resist licking his lips. 

The robot stopped his touches and stood up, bringing Papyrus up with him to move onto the bed, sitting facing one another. Mettaton nuzzled at his neck and nipped at the soft juncture where his jaw line begins. "Papy, dear," He whispered. "While I rested, my hard drive was set to look up information on intimacy. . . The type I know you want."

"O, OH?" Papyrus trembled. He reached down to undo his shorts. Wearing clothing was becoming too much. His hand was stopped. Mettaton gave him a predatory look, no longer the innocent little robot he was back in the living room between his legs.

"No need to rush, deary! I want to show you something first." Mettaton said. He softly smiled at him, relaxing Papyrus as he leaned his head back to allow more biting in the tiny joints in his neck.

Keeping his lips to his neck, Mettaton had him focused on the sensation while he opened his hard drive in secret. He didn't let him know but he had emailed Alphys and she sent the data in the 'relations' chip to his body so the database could go ahead and download while he slept. Right now all Mettaton had to do was activate the data then let instincts take over.

Pressing a button beside the casing in his middle, the robot was able to activate his new upgrade, fully downloaded and ready for use. Mettaton gasped at first. He felt a bit of movements in his wires and mechanics but he saw no change in his physical appearance. He frowned until Papyrus cupped behind his head and gently kissed him. Mettaton smiled against him, parting his lips and licking at his teeth teasingly. Papyrus gasped and let him lick the inside his of mouth, tasting all he possibly could. The skeleton struggled to not reach down to undo his trousers. His erection pressed on the fabric of his shirts, straining as a large outline. It was starting to feel painfully hard. 

"METTA, OH MY GOD." Papyrus whimpered, turning his head away. "WHAT'S GOTTEN INTO YOU? YOU DO NOT USUALLY SHOVE YOUR TONGUE DOWN MY THROAT." 

The star giggled. He licked his lips as he reached down to his partner's shorts, undoing them and beginning to tug them down. If his new download wanted to be slow, he would go ahead with what he wanted. And that was his beautiful sugar skull in his mouth.

"True. But today I want a full taste of you." 

Papyrus blinked, surprised and still utterly turned on. He grit his teeth roughly together, his shaft taken into Mettaton's hand. He shuddered as he was given a few light strokes just before Mettaton pressed a kiss to the tip. 

Mettaton moaned softly. He parted his lips an took the swelling head into his mouth, sucking gently around it. He could feel him twitch on his tongue. It sent a heat to his soul but he ignored it and welcomed more cock into his mouth. Papyrus tasted so sweet, it was sort of addicting. Mettaton had no gag reflex and felt grateful for that as he took the long organ into his throat.

Papyrus groaned. He sat back onto his pillows, one arm holding him up by the elbow and his other hand tangling into his lover's soft locks of hair. He tugged gently on his hair with a cry of pleasure. Heat engulfed his cock and the other sucked hard on him. When Mettaton's head began to bob, Papyrus felt as if he were going to cum right then. He held it it and moaned to the way Mettaton's throat felt around him. So hot and velvety. Papyrus whimpered, squirming his hips slightly to try bucking needily into his throat. The urge to cum was so strong. Mettaton sucked harder still when he began to fidget. 

"OH MY GOD!" Papyrus gasped. "I CAN'T. . . OH, NO. . . CUMMING!" 

Mettaton brushed a piece of hair calmly from his face as he relaxed his throat and let his boyfriend buck against his face. The energy of utter pleasure that Papyrus gave was causing him to feel an unfamiliar heat in his groin, soul thumping fast in its casing. His body was becoming so hot that he panted as sweet, salty semen spurted down his throat. Mettaton swallowed it, still sucking lightly to try and get him fully finished. It easily was successful. Papyrus shuddered, laying back feeling hot and his body tingled from the orgasm he rode out. Mettaton slowly pulled his head back and kept the other's now soft shaft held in his hand. 

"MY DEAR. THAT WAS. . OH GOD. ." The skeleton panted. He cried out when his shaft was given a little tug. He let his head fall back with a moan. Getting hard again, Papyrus whimpered. It felt like his soul was boiling with lust. He grit his teeth again, opening his legs as he felt his soul create a new opening between his legs a little bit under his dick. It was puckered and eager to receive attention. Mettaton looked surprised at him just before grinning big. 

"Do you want me to fuck your ass, Papy, love?" Mettaton giggled. He kept up with stroking his shaft. His free hand gave his balls a gentle massage for a second then moved to the hole matching the cock he was handling. 

Moaning, Papyrus nodded. His hips lifted a little. "PLEASE. . . I CRAVE SO MUCH MORE. . ." 

"Well. . . If you're going to beg." Mettaton brought his fingers into his mouth and licked them slick with his saliva before positioning two fingers to his lover's hole. "Relax. I don't want to hurt you, sugar skull."

After giving a nod of understanding, his lover whimpered when he pushed his two fingers inside the tight ring of muscle. Mettaton was gentle and careful. He stroked the other to keep his mind on the pleasure, which kept him relaxed. Papyrus' tight walls began to stretch around the invading fingers the further they pushed inside.

"METTA," Papyrus moaned softly. He eyed his soul casing, watching how the passionate pink spirit squirmed. "WHY DO YOU NOT OPEN THIS ?"

Pausing,Mettaton followed his gaze. "Well. . . I've never really. . . Tried to. ."

"THERE'S NO R, RUSH!" Papyrus nervously mumbled. He gasped, the other's fingers now buried fully inside him. The two fingers pressed lightly on a little nerve deep inside him.

Mettaton curled his fingers against the spot, watching how it made Papyrus squirm and moan. He saw his cheeks were painted deep orange- As if showing this lustful side of himself is embarrassing. Mettaton pulled his fingers back only to thrust them back fully inside. Papyrus cried out loudly, his spine arching. Mettaton paused. The hand around Papyrus' orange magic cock unwrapped and went to his case. A few switches went on inside Mettaton, he could feel something between his legs but ignored it. Papyrus whined at how he was no longer being touched but quickly went wide eyed when seeing his boyfriend now had a tight pair of lips between his thick silicone thighs.

He opened his mouth to ask when the other had requested such an upgrade but Papyrus was stopped by the sight of Mettaton opening the see through case located where his stomach should be. Papyrus gulped nervously at seeing how the other's soul glowed pink and twitched in excitement. The sight made his own soul feel giddy. He had always been able to see it in the case, but this felt more personal and up close. Papyrus offered a smile that was met with a soft kiss.

"Papy, my love," Mettaton let his soul openly work on its own, beginning to form an erect organ on his groin. "You're the only one allowed to see me like this. You got that?"

Feeling his body surrounded by heat from the sight of Mettaton's new genitals, Papyrus could only shyly nod. He stared at his tight lips, a long cock replacing a clitoris. The slender skeleton let out a soft whimper. He forced himself to meet Mettaton's unfaltering gaze. "COULD WE MAYBE. . . GO A LITTLE FURTHER?"

Going wide eyed, surprised, he went silent. Then Mettaton wrapped his hands around the other's femurs and tugged him forward so that his groin pressed to Papyrus' ass. "You're sure you want to do this, my beautiful skull-head?"

"C, CERTAINLY!" Papyrus knew his cheeks were no doubt the deepest orange ever seen on the colour spectrum. He could feel his boyfriend's cock twitching from just being near his entrance. It sent shivers down Papyrus' spine. "I KNOW I AM IN GOOD HANDS."

Without another word Mettaton placed himself on top of Papyrus, pressing his swollen tip to his puckered opening. He pressed his lips to his teeth in a loving kiss, his hips pushing forward as he began to push into Papyrus.

"OH GOD," Papyrus groaned. It stung to have a larger intrusion. He wrapped his arms around his lover's back, clinging and feeling the hotness of their souls touching. "METTA."

Mettaton paused. He was not even half way in yet. But he was being squeezed a little too much. With a soft whir, he nuzzled the skeleton's skull gently. He felt him relax. Papyrus had gotten so worked up over how their souls felt that he had tensed without realizing it, but now he was alright. Papyrus groaned at feeling Mettaton continue pushing into him. Soft words of encouragement left black painted lips, lovingly telling him how much he loved him and now he was so happy that this was with him. Papyrus felt as if he could burst with happiness- Though, instead he let out a sharp yell when Mettaton pushed suddenly into the rest of him. Whimpering, Papyrus looked up at his lover to see Mettaton looked quite ashamed for possibly hurting him.

"I, I'm so-"

"DON'T BE!" Papyrus  hooked his feet against the other's lower back. With this moment of pause he could let himself adjust.

"Are you ok. .?" Mettaton's voice came out as a whisper.

The other nodded.

Pulling back  slowly, Mettaton pushed himseld back inside. He bit back a groan. The warmth wrapped around him made his shaft delightfully twitch. Papyrus clung to him with his arms and legs, keeping close and pressing his phalanges encouragingly onto his partner's metal shoulder blades. His spine arched off of the mattress as he felt a bundle of nerves struck by Mettaton, which sent a white wave of pleasure through the magical skeleton.

"OH, GOD, METTA. .!" Papyrus gasped. He rocked his hips forward to meet the thrust pushed deep into him. "M, MORE. . PLEASE, MORE!"

Mettaton grit his teeth together to keep in an especially loud moan, his thrust becoming more precise and rough. It filled him with happy lust to watch Papyrus squirm in pleasure every time he bucked into his sweet spot with his tip. But he knew there could be more pleasure. With a cat-like smirk Mettaton gripped Papyrus' pelvic bone to buck harder into his entrance. His other hand guided one of his love's hands down so that his dick could get attention. He took pleasure in how Papyrus moaned his name when they stroked his cock up and down with both of their hands, squeezing him and gripping him in a soft way that made Papyrus shudder and gasp. It made Mettaton feel so hot and attracted to his lover, his new upgrade causing his arousal to make his new vagina wet with.arousal- Almost dripping by now  Papyrus gripped his hand harder on his back, his ass starting to tighten with every thrust. He could feel himself about to release again.

"METTA, I'M ABOUT TO. . !"

"Go on, darling, feel good for me."

Shuddering and squirming into the delicious friction wrapped around his cock and pushing in his ass, Papyrus only lasted a few more seconds. He came with a loud cry of pleasure, releasing on both of their hands, his orange magic covering their hands with Papyrus' seed.

Collecting his calm, Papyrus looked up at the other and smiled shyly. "YOU DIDN'T. . ?"

Mettaton shook his head. He pressed soft kisses to his sweetheart's forehead, beginning to move his hips once more in a soft thrust. Though now his lover was limp, his hole was still hot and wrapped perfectly around him. Mettaton held in a moan as he felt his cock start to tingle with pleasure, twitching slightly while an odd sensation overcame him. The celebrity robot bucked harder into the other, sort of ignoring how the other cried out so that he may focus on the pleasure rising in his soul. Mettaton audibly groaned now, his shaft responding to the sensations overtaking him until he couldn't take it anymore- Spurting passionate pink cum into his love's hole.

"S, sorry. I shouldn't have came in. . .side. ." Mettaton said slowly. 

Papyrus snickered. The sticky feeling didn't bother him. It meant they both had fun and he was happy about it. He leaned up to kiss him, unwrapping their hands from his limp cock to wrap his arms around his neck and keep close.

"Papy. ." Mettaton moaned against his teeth. "I'm still. ."

Papyrus pulled back. He arched slightly at feeling the other start thrusting inside him, slow and gentle.  "I FEEL WHAT Y,YOU MEAN. WOULD YOU LIKE TO. . DO 'IT' AGAIN?"

Mettaton pulled out. He gave himself a few strokes only to let his hand wander down, caressing the wet lips between his thighs. He moaned, slipping a finger inside. A soft groan caught his attention, causing him to catch a glimpse of Papyrus stroking himself back to hardness.

"Sugar skull?" 

Papyrus blushed a little deeper. He took Mettaton's hips into his hands and squeezed them lightly. Mettaton gasped, stopping with touching himself to move on top of Papyrus, rubbing their intimate parts against one another. 

"Papy, love," Mettaton moaned. He could feel the other's tip pressing just outside his hole, but never pushed inside. It felt like pure torture. "Please. . I want to feel it, too."

His request was met with Papyrus pressing his cock inside his vagina, stretching the tight hole around his girth. Mettaton cried out. He tried pushing his hips down to make sure every thick inch went in, but he wasn't exactly in control. It sent shivers through the robot as his lover filled him halfway only to pull out and slowly push back in, teasing his velvety hot entrance.

"HOLY CRAP," Papyrus groaned. He struggled to keep composure while he bucked into his boyfriend, careful with his new upgrade. "SO. . T,TIGHT." 

Moaning happily, Mettaton grinned lazily. He leaned forward and put a hand on either side of his love's skull in order to support himself. He pressed his groin down, managing to press the other's cock deeper into him. It made him moan louder, feeling how the tip pressed on something that made him shudder. Papyrus gripped his hips tighter in his phalanges as he bucked harder into him, feeling how he squeezed around him every time he buried into his heat.

"God. . . Oh God. . . Papyrus!" Mettaton cried out. He gasped as the other kept on pressing harder and harder into him, causing his insides to twitch with pleasure. "More! I wanna cum so bad, Papyrus!"

The way his robotic love moaned from what he did only encouraged the skeleton to push faster into him, adoring the clenching around him. Papyrus groaned, lifting himself on one elbow while his other hand stayed gripping one hip. Mettaton brought a hand to his cock made of his own soul magic and stroked it hard with every pump inside of him. They both moaned loudly in ecstasy of pleasure. A loud cry left Papyrus as he started to feel like he was going to finish again. He whimpered, leaning up to nip at Mettaton's synthetic neck. 

"Darling, gonna cum. . ." Mettaton moaned deeply. He tossed his head back and gasped. Precum dripped from his tip. "I can't hold it, Papy!"

"M,ME TOO!" Papyrus gasped. He bucked hard into the other before releasing inside, his back arching slightly from the mattress. He watched with his own orgasmic bliss as Mettaton couldn't stop himself from humping his hand eagerly before coming on his own fingers and the cry of pleasure that followed it, his walls clenching Papyrus.

It took a little while before both of their orgasms were finished, completely rode out. They shared a soft kiss while Mettaton eased himself from the skeleton's now limp cock, which went to disappearing back into his soul, totally spent. His followed suit- Satisfied. Mettaton turned off his upgrade so his body would go back to normal. He laid down beside Papyrus and blushed as he was instantly brought into a pair of boney arms.

"Darling?" Mettaton questioned, raising his gaze to meet with a loving look in his lover's eye sockets. He blushed a deeper pink, burying his face against the other's ribcage to hide his flustered expression. 

Papyrus kissed the top of his boyfriend's hair and hummed peacefully. "I JUST. . ." His voice dropped to a whisper. "Love you so much, Metta."

"I love you, too." Mettaton whispered back. He relaxed in his arms, his cheek flat on his sternum. 

A peaceful silence fell between the two. It was only broken by Papyrus yawning. He closed his eyes and took in the warmth of how it felt to hold Mettaton. Their relationship had some boundaries that couldn't be crossed, but now he felt as if he and Mettaton crossed over the borders. Their souls touched and their bodies came together with love that they felt for one another. They both knew that there was no way another person was going to be allowed to see this side of each other except them. Especially in Mettaton's case- No one else is allowed to feel his fluttering soul with the exception of Papyrus. 

"Hey," Mettaton sat up from the embrace. "Promise me our relationship won't be weird after this. Ok?" 

Papyrus couldn't help chuckling. Seeing how he earned an offended look, he quickly put his thoughts to words. He sat up, taking Mettaton's hands into his own. "You have my word, my dear." He whispered. "Besides, I can only see our relationship growing stronger." 

Cheeks full pink, Mettaton knew he must look like a flustered mess. But that was OK. He didn't have to stay cool and beautiful with his boyfriend. He's learned that a while ago. "Stronger? R, really?" 

"Of course!" Papyrus smiled at him. He cupped his hands on both sides of his face and brought Mettaton into a deep kiss. 

Moments later they parted and snuggled back into a comfy embrace in each other's arm. The heat from their lust was gone. All there was to feel now was utter love. The upgrades were wonderful and all, but they were wanting to be intimate in a more innocent way after everything.

**Author's Note:**

> What did you think? Feel free to comment your opinion on my work! All feedback is appreciated.


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